Tractor.



C. E. SEARCH.

TRACTOR.

APPLICATION FILED Nov, 29, 1915.

Patnted May 22, 1917.

CHARLES EDWIN SEARCH, OF MILWAUKEE, WISCONSIN, ASSIGNOB T ALLIS- CHALMERS MANUFACTURING COMPANY,

CORPORATION OF DELAWARE.

or MILWAUKEE, Wisconsin, :A'

TRACTOR.

T 0 all whom it may concern." 7

Be it known that 1, CHARLES EDWIN SEARCH, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented a certain new and useful Improvement in Tractors, of which the following is a specification...

This invention relates to improvements in tractors,.and particularly to improvements in the construction of devices for adjusting the rollways of endless tractor belts.

An object of the invention is to provide an endless track mechanism for tractors, which is simple in construction and eflicient in operation. One of the more specific objects is to provide simple and elficient means for adjusting the rollways of an endless track or tractor belt. v

It has heretofore been proposed to drive a tractor by means of one or more endless track mechanisms each comprising a continuous belt or band of thread links which engage an endless series of rollers which in turn engage a rollway formed on the tractor frame. Adjustment of the rollway in some of these prior devices, was accomplished by making a portion or "section of the rollway yieldable, and providing means for distorting this yieldable portion in order to produce the desiredadju'stment. It has been found that the adjustable yieldable portion of the rollway would under certain conditions of operation of the tractor, be subjected to severe strains which would undesirably distort the roller support, and it is an object of the present invention to overcome this undesirable distortion. This result is accomplished primarily by making the heretofore yieldable adjustable rollway portion rigid and capable of withstanding even the severest strains to which it may be subjected.

A clear conception of an embodiment of the invention may be had by referring to the drawing accompanying and forming a part of this specification in which like reference characters designate the same or similar partsin the various views.

Figure 1 is a; side elevation of an endless track mechanism for power driven tractors.

Fig. 2 is an enlarged fragmentary side Specification of Letters Patent. Patented May 22, 1917, Application filed November as, 1915. Serial No. 64,575. I

elevation of the leading end of theframe and portions of one of-the rollways.

Fig. 3 is an enlarged transverse vertical section through the device disclosed in Fig. 2, the section being taken along the line III-I1I of Fig. 2 looking in the direction of the arrows.

Fig. 4 is a side elevation, partly-in sectlon, of another form of an adjusting devlce for the rollways of tractors.

The term rigid as employed throughout the specification and claims is intended to apply only to elements'such as castings or other parts which are not capable of yieldlng an appreciable amount due to 'strains to which the elements are subjected during normal operation of the device. The term yleldable on the other hand, is intended to apply to those elements which do permit an appreciable amount of distortion or flexure when subjected to strains during normal operation of the machine.

The assembled mechanism disclosed in Fig. 1 comprises essentially a main frame 1 havingbifurcated.trailing and leading end portions within the bifurcations of which the sprockets 3', 4, are located and normally operable. The rear driving sprocket 3 is secured to a shaft 5 which is rotatably mounted in rigid bearings at the rear or trailing end of the frame. 1. The front idler sprocket 4 is secured to a shaft 6 which is rotatably mountedin adjustable bearings 7 at the front or leading end of the frame 1. .The mid-portion of the frame 1- is provided with a journal .bearing2 which engagesthe truck axle in the usual manner.

The lower extremity of each of the rigid adjusting links is pivoted to the leading end adjusting device 17 one end of which is mounted in the forwardly projecting bifurcated portion of each of the adjustable bearings 7 A yieldable rollwa-y portion 9 is secured to the front of each link 8 by means of a bolt 25. The rear end of each yieldable portion 9 is-supported from the top of the bearing 7 by means of an adjustable brace 19. Each of the rollway portions 10 is supported from upper surfaces of a bearing 7 journal bearing 2, and frame 1, by means of in any suitable manner.

suitable braces 20, 21, 22, respectively. The upper portions 10 of the rollways are provided with rear extensions Which extend downwardly in proximity to the lower portions 11 of the rollways. The lower rollway portions 11 are fixed to the bottom frame 1 Endless series of rollers 12, the successive rollers of which are connected by means of links 13, engage the rollways. Each endless track comprises a continuous series of tread links 14 which are connected by means of suitable pins 15. The tread links 14 engage the sprockets 3, 4, and have surfaces adapted for engagement with the rollers 12.

Each bearing 7, see Figs. 2 and 3, is adjustable relatively to the adjacent frame 1, by means of an adjusting device 16, one end of which engages an abutment on the frame 1 and the other end of which engages an end of the bearing 7. These adjustin devices for the bearings 7 provide means or either allowing or taking up slack in the endless track by adjustment of the sprocket 4 relatively to the sprocket 3. The bearings 7 are fixed in adjusted position relatively to the frame 1 by means of suitable clamping devices or bolts 23, 24. The links 8 are ad- 'ustable to vary the lengths of the rollways y means of the adjusting devices 17. Each adjusting device 17 comprises concentric bearing portions 27 29, which are rotatable in alined bores in the front portion of the bearing 7. Eccentric portions 28 are located intermediate the bearing portions 27, 29, and engage the slots 26 in the upper ends of the links 8. The adjusting devices 17 are operable by means of squared end portions 38 and are fixed in adjusted position by means of nuts 39 and locking set screws 30,

the latter of which engage suitable recesses in the peripheries of the bearing portions 29. Upon rotation of the adjusting device 17, the adjacent links 8 and the rollway portions 9 carried thereby are moved relatively to the leading end of the frame 1.

In the device disclosed in Fig. 4, the entire front portions of the rollways are formed upon rigid elements 31 which are adjustable in directions parallel to the front sprocket bearings 34 by means of adjusting devices 33. The bearings 34 are adjustable relative to the frame 36 by means of adjusting devices 35. The upper and lower rollway portions 32, 37, are formed similar to the corresponding elements in the disclosure of Fig. 1, andmaly be made either yieldable or rigid, as desire I During the normal operation of the device, the rear sprocket 3 is rotated by means of any suitable mechanism, causing the successivetread links 14 to move in an antimay be done by first loosening the nuts on the bolts 23, 24, and the nut 39 and set screw 30 on each of the adjusting devices 17, after which manipulation of the adjusting devices 16 in the proper direction will cause the bearings 7 to move relatively to the frame 1 and to alter the position of the front sprocket 4. After the sprocket 4 has been properly adjusted, the nuts of the bolts 23 should again be clamped in place, after which proper adjustment of the links 8 to produce ,proper tension on the roller chains, may be made by manipulating the adjusting devices 17. With the rollway portions 8, 9, properly adjusted, the nuts 'on the bolts 24 may again be clamped in position, thereby securely fixing the braces 19, 20, and the bearings 7 in place. If it is desired to simultaneously adjust both the rollways and the sprocket 4, this may be done by merely adjusting the bearings 7 without manipulating the adjusting devices 17 It will thus be noted that the sprocket 4 and the rollways may be adjusted either in dependently of each other or simultaneously. The provision of rigid adjustable portions for the rollways at the leading ends thereof, eliminates undesirable distortion of the rollways due to impact of the front portion of the endless track with objects such as stones whichmay be in the course of the vehicle.

While the portion of the doorway which is ordinarily subjected to undue strains, is that portion which is provided with the link 8 in the disclosure of Fig. 1, it may be desirable to make the entire front portion or any other portion of the rollway rigid and adjustable. As disclosed in Fig. 4, the entire front portion of each rollway is formed on a rigid element 31, which is adjustable rela-- tively to the bearing 34 and, the frame 36, by means of an adjusting device 33. In this case as in the case of Fig. 1', the rollways may either be adjusted simultaneously with or independently of the adjustment of the sprocket bearings 34. It may also be desirable to provide adjustments for the rollways at the rear of the frame, such modification being within the scope of this invention.

It should be understood that it is not desired to be limited to'the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

It is claimed and desired to Letters Patent,

1. In combination, a frame, a rollway carsecure by ment.

an. adjustable rigid portion located at the leading end of said frame, rollers engageable at said rigid portion with said rollway,

a traction belt engageable with said rollers,

and means for adjusting the tension of said belt, said rigid rollway portion being adjustable independently of said tension adjust- 3. In combination, a frame, av rollway carried by said frame, said rollwa comprising a substantially horizontally ad ustable rigid portion located at the leading end of said frame, rollers engageable at said rigid portionwith said rollway, a traction belt enga cable with said rollers, and means for ad usting the tension of said belt, said rigid rollway portion being adjustable independently of said tension adjustment.

4. In combination, a frame, a rollway carried by said frame, said rollway comprising an adjustable rigid portion and a yieldable portion continuous with said rigid portion,

rollers engageable with said rollway, and a traction belt engageable with said rollers.

5. In combination, a frame, a rollway carried by said frame, said rollway comprising a rigid link havingone end pivoted to said frame and having its opposite end adjustable, rollers engageable with said rollway, and a traction belt engageable with said rollers.

6. In combination, a frame, a rollway carried by said frame, rollers engageable with said rollway, sprockets carried by said frame, a traction belt engageable with said sprockets, and means for simultaneously adjusting said rollway and at least one of said sprockets, said rollway also being adjustable independently of said sprockets.

7. In combination, a frame, a rollway carried by said frame, said rollway comprising a rigid link having one end pivoted to the lower portion of the. leading end of said frame and having its opposite end adjustable toward and away from the leading end of said frame, rollers engageable with said rollway, and a traction belt engageable with said rollers.

8. In combination, a frame, a rollway carried by said frame, said rollwa comprising a rigid link having one end plvoted to the lower portion of the leading end of said frame and having its opposite end adjustable toward and away from the leading end of said frame and a yieldable portion continuous with said rigid portion, rollers engageable with said rollway, and atraction belt engageable with said rollers.

In testimony whereof, the signature of the inventor is affixed hereto.

CHARLES EDWIN SEARCH. 

